DESCRIPTION: (Applicant's abstract) The yeast genome sequence is now known, a major technical accomplishment that offer unprecedented opportunities for study of the cell biology of the simplest eukaryote. Knowledge of the interactions of regulatory and structural proteins with DNA in vivo is important for application-of the yeast DNA sequence to its function. This proposal addresses how to accomplish that goal. It builds on emerging applications of DNA methyltransferases to map protein-DNA interactions in living cells by developing methodology that will allow resolution (<l0 base pairs) study of interactions over extended regions of the S. cerevisiae genome. It describes methodology which will allow quantitative assessment of protein-DNA interactions with automated techniques that are appropriate for large regions of the yeast genome and exportable to larger eukaryotes. To illustrate the utility of the approach, we will map the chromatin organization of about half of chromosome III. Comparing portions of the structure with that determined by classical methods. Many other laboratories are highly interested both in chromatin structure and its role in DNA function and in interactions of regulatory proteins with DNA. To facilitate the research of these scientists, we propose a service which will provide chromatin mapping data for other regions of the yeast genome of interest.